Glue bond tester



Aug. 13, 1968 l J. O- SKUNDBERG GLUE BOND TESTER 4 Sheets-Sheet 1Original Filed Dec. 4, 1963 iau INVENTOR (JAM 5 0. SKI/M05526 BYgiLQTWEdM;

ATTORNEY Aug. 13, 1968 1.1.20. SKUNDBERG GLUE BOND TESTER Original FiledDec. 4, 1963 4 Sheets-Sheet 2 1963 1.0. SKUNDBERG 3,396,578

GLUE BOND TESTER 4 Sheets-Sheet (5 Original Filed Dec. 4, 1963 74 7.9 34] f2 52 Z0 9,? 0 4 F7 f0 INVENTOR 1968 J1 o. SKUNDBERG 3,396,578

GLUE BOND TESTER Original Filed Dec. 4, 1963 4 eet 4 Z45 TDR /55 T d 1754 1951 192 L 151- 944 199 K "I 172 199 j 199 1 1 59 9 i K; -191 $9 9 199CR L150 A 159 l H l 152 155" 3 5 CT -4 INVENTOR F/ 6. f2 'JAm-s 0;Ska/wanes ATTORNEY United States Patent "ice 3,396,578 GLUE BGND TESTERJames 0. Shundberg, St. Paul, Minn, assignor to Waldorf Paper ProductsCompany, St. Paul, Minn, a corporation of Minnesota Continuation ofapplication Ser. No. 327,394, Dec. 4, 1963. This application July 11,1966, Ser. No. 574,862 8 Claims. (Cl. 73150) This application is acontinuation of my previously filed application Ser. No. 327,894, filedDec. 4, 1963, now abandoned.

This invention relates to an improvement in glue bond tester and dealsparticularly with an apparatus designed to test the effectiveness of anadhesive bond between two surfaces.

For many years the determination of the effectiveness of differentadhesives on various types of paperboard has been somewhat of a hit ormiss proposition. Considerable difficulty has been experienced inproviding a uniform means of testing the adhesive bond. Theeffectiveness of the seal between tWo pieces of paperboard varies withthe amount of adhesive applied, with the amount of pressure used toaffect the seal, and with the time involved between the time theadhesive is applied and the time the test is made. Certain types ofadhesive will work very effectively on some surfaces and not on others.Some adhesives will work effectively on one type of gluing machine wherethe parts adhered are held under compression for a relatively longperiod of time, but will not be effective if the sheets are undercompression for a shorter time period. In most carton converting plants,the effectiveness of the gluing operation is determined by trial anderror. However, such a method can result in very considerable losses,for if the glue bond of the manufacturers joint is not effective,thousands of improperly glued cartons may pass through the gluer beforethe error is noticed.

An object of the present invention resides in the provision of anapparatus for measuring the effectiveness of a glue bond in which mostof the variables are eliminated. A means is provided for applying ameasured thickness of an adhesive to one of the surfaces to be adhered.A strip of paperboard which forms the second surface to be adhered thenis applied to the adhesive and pressed into place by a predeterminedcompressive force. At the completion of the adhering operation, a timeris started to permit the two surfaces adhered to remain in face contactfor a predetermined length of time. At the completion of this timeperiod, a means is provided for peeling one strip from the other. Theamount of force required to separate the two surfaces is measured by asuitable indicator. The point at which the adhesive bond ceases toseparate and the adhesive starts to remove portions of a surface of thepaperboard is noted. As a result, the type of adhesive which should beused for adhering various surfaces can be readily determined, and theeffectiveness of a certain type of adhesive with certain types of paperor paperboard can be predicted in advance to the actual gluingoperation.

An object of the present invention resides in the provision of a meansfor supporting a paperboard base sheet on a fiat surface, a means forapplying a predetermined thickness of adhesive to the surface of thebase sheet, and a means for applying a predetermined sealing pressure toeffect the bond between the applied strip and the base sheet. Thislatter means preferably comprises a roller of a desired weight which canbe moved throughout the length of the applied strip first in onedirection and then in the other. A carriage is supported for movement ona track- Way extending parallel to the applied strip and is movedlongitudinally of the trackway at a predetermined speed.

3,395,578 Patented Aug. 13, 1968 The carriage yieldably supports an armbearing a clamp which engages one end of the applied strip. As thecarriage moves through its path, the clamp acts to peel the appliedstrip from the base sheet. A means is provided so that as the arm yieldsrelative to the carriage, the relative movement between the arm and thecarriage operates an indicator which discloses the pulling forcerequired to tear the adhered surfaces apart.

A further feature of the present invention resides in the provision ofan apparatus of the type described which includes a scale mounted upon aflat surface adjoining the base sheet which is in a predeterminedrelation to the base sheet and to the strip adhered thereto. This scalemay be used to provide a determination of the point at which theadhesive bond ceases to separate and the pulling force starts to tearthe surface of the paper. By this means, an accurate determination ofthe setting time of the adhesive may be obtained.

A further feature of the present invention resides in the fact that thethickness of the layer of adhesive may be accurately determined. A poolof adhesive is placed upon the base sheet in a predetermined location,and the adhesive is spread longitudinally of the base sheet by aspreading bar having ends which extend slightly below the level of thecenter portion of the bar. As a result, the thickness of the adhesivefilm is controlled by the space between the center portion of thespreading bar and the base sheet.

These and other objects and novel features of the present invention willbe more clearly and fully set forth in the following specification andclaims.

In the drawings forming a part of the specification:

FIGURE 1 is a top plan view of the glue bond-tester in readiness foruse.

FIGURE 2 is a side elevational view which is partially broken away andwhich is shown partially in cross section along the line 2-2 of FIGURE1.

FIGURE 3 is a view similar to FIGURE 1, but showing the glue bond testerin operation.

FIGURE 4 is a perspective view of the spreader used for applying theadhesive to the base sheet.

FIGURE 5 is a sectional view on a vertical plane through the spreaderillustrated in FIGURE 4.

FIGURE 6 is a perspective view of the pointer operating arm.

FIGURE 7 is a top plan view showing the pointer and pointer operatingarm in engagement.

FIGURE 8 is a horizontal section beneath the platform of the movablecarriage, the position of the section being indicated by the line 88 ofFIGURE 9.

FIGURE 9 is a vertical sectional view on the line 99 of FIGURE 1.

FIGURE 10 is a vertical sectional view through the indicator operatingmechanism, the position of the section being indicated by the line 10-10of FIGURE 1.

FIGURE 11 is a detailed view of the clamp used for gripping the ends ofthe paperboard strip.

FIGURE 12 is a diagrammatic view of the wiring diagram of the apparatus.

The tester is indicated in general by the letter A and includes a tableor platform 10 which is supported above a suitable supporting surface,not illustrated in the drawings, by a rectangular base portion 11 ofchannel-shaped cross section.

A pair of parallel slides 12 and 12a are supported above the surface ofthe table 10 by means of supporting blocks 13 located near opposite endsof the table. A gear rack 14 extends longitudinally of the table 10between the slides 12 and 12a. For a purpose which will be laterdescribed. A carriage 15 is slidably supported upon the track formed bythe parallel guides 12 and 12a. As is indi- 3 cated in FIGURE 9, thetable includes a platform 16 having downwardly extending lugs 17, nearopposite ends thereof and which support bearings or bushings 19encircling the slides 12. The platform 16 is thus slidably supportedupon the track and is generally horizontal.

A sleeve 20 extends vertically through the platform 16 near one endthereof and is provided at its upper end with a peripheral flange 21which overlies the surface of the platform. The flange 21 and sleeve 20are held in fixed position by cap screws 22 or other suitable meansextending through the flange and into the platform 16. A pair ofvertically spaced bearings 23 and 24 are supported within the sleeve 20and are held in spaced relation by a spacer sleeve 25. The lower bearingis held in position in the sleeve 20 by the heads of retaining bolts 26.

A shaft 27 is rotatably supported in the bearings 23 and 24 and isprovided at its lower end with a pinion 29 which is in mesh with theteeth of the rack 14. The lower portion 30 of a coupling 31 is securedto the shaft 27 and rests upon the upper bearing 23 to hold the shaftfrom axial movement. The upper portion 32 of the coupling 31 is securedupon the vertical shaft 33 of a reduction gear unit 34 driven by theshaft 35 of a motor 36. The motor 36 is supported by spacer blocks 37and secured to the plaform 16 by cap screws 39.

An elongated generally rectangular block 40 encircles the slide shaft 12and includes a pair of longitudinally spaced bearings 41 which arerecessed into apertures in opposite ends of the block. As indicated inFIGURE 10 of the drawings, a roller 42 is mounted on a pivot pin 43threaded into the upper surface of the block 40 near the center thereof.The roller 42 is slidable in a slot 44 which extends through theplatform 16. An enclosing housing 45 preferably overlies the slot 44 toprevent foreign material from entering the slot. The block 40 issomewhat shorter than the length of the platform 16, the platform beingindicated in dotted outline in FIGURE 8 of the drawings as the positionof the section is immediately below the level of the platform. A stoplug 46 extends downwardly from the platform 16 and an adjustable stoppin or screw 47 extends through the lug 46 in the direction parallel tothe axis of the slide 12 to engage the end of the block 40 and to limitmovement of the block in one direction. A second stop lug 49 is securedto the under surface of the platform 16 and includes a bearing orbushing 50 through which the slide 12 extends. A spring 51 is interposedbetween the stop lug 49 and the block 40 encircling the slide 12, thepurpose of the spring 51 being to urge the block 40 against theadjustable stop pin 47.

As indicated in FIGURES 8 and 10 0f the drawings, a gear rack 52 ismounted upon the side of the block 40 and the teeth of the rack 52 arein mesh with a pinion 53 mounted on a vertical shaft 54, the upper endof which extends through the platform 16. An upper bearing 55 is mountedin the platform 16 and a lower bearing 56 is mounted in an L-shapedbracket 57 secured beneath the platform 16. The bearings 55 and 56support the vertical shaft 54. The upper end of the shaft 54 extendsthrough an indicator mount 60 and a bearing 61. A reduced diameter upperend 59 of the shaft 54 extends into or through an indicator drive disk62 and is secured thereto by a pin or set screw extending radially ofthe disk 62 as indicated in FIGURE 6 of the drawings at 63. Theperipheray of the drive disk 62 is provided with a downwardly projectingarm 64. The arm 64 is drilled on a plane normal to the axis of the shaft54 to accommodate a set screw 65 extending tangentially to ahypothetical circle about the shaft axis as indicated in FIGURE 7. Theindicator comprises a disk-like portion which encircles the bearing 61and has an integral pointer arm 67, one edge 69 of which is on avertical plane through the axis of the shaft 54. The bearing encirclingportion of the indicator is also provided with a projecting arm 70 whichalso terminates in a shoulder 71 which is on a vertical plane throughthe axis of the shaft 54 which, in the structure illustrated, isdiametrically opposed to the pointer edge 69. This shoulder 71 may beengaged by the set screw 65 to rotate the freely rotatable indicatorpointer in unison with the shaft 54. A pair of vertical flanges 72 aresupported on the side of the block 40 opposite that supporting the rack52. A pivot shaft 73 extends through the flanges 72 on an axis parallelto the axis of the slide 12. A pivot block 74 is transversely drilled toaccommodate a bearing 75 which encircles the pivot shaft 73. One cornerof the pivot block 74 is rounded as indicated at 76 to permit thepivotal movement of the pivot block through an angle of approximately 90from a vertical position to a substantially horizontal position. A clampsupporting shaft 77 is provided with a reduced diameter threaded endportion 79 which is threaded into the outer vertical surface of theblock when the block is in vertical position. The clamp supporting shaft77, in this position of the pivot block, extends parallel to the table10 and is spaced somewhat above the level of the table. The clampsupporting shaft enters the block 74 below the level of the axis of thepivot shaft 73 to urge the block into one extreme position by itsweight.

A clamp indicated in general by the numeral 80 is secured to the end ofthe shaft 77 by a cap screw 81 or other suitable means. The clamp 80 inthe form illustrated includes a lower arm 82 having a pair of spacedparallel upwardly projecting ears 83 which encircle a portion of the capscrew 81; and an upper arm 84 which includes a downwardly extending ear85 which extends between the ears 83 and also encircles a part of thecap screw 81. The lower arm 82 is provided with an upwardly projectingjaw 86 on one end thereof, and the upper arm 84 is provided with acooperable downwardly projecting jaw 87 on one end. A spring or similarresilient means 89 is positioned between the other ends of the arms tourge the jaws in clamping position.

In order to open the jaws, a pin 90 is provided extending through theother clamping arm ends and through the spring 89, the pin is providedwith a head 91 at its lower end. The upper end of the pin 90 extendsbetween a pair of eccentrics 92 and are pinned thereto by a pivot pin93. The eccentrics 92 are connected by an operating handle 94. Bypivoting the handle- 94 in a clockwise direction as viewed in FIGURE 11,the spring 89 may be compressed and the jaws 86 and 87 opened to admitthe end of the paperboard strip.

As indicated in FIGURES 1 and 3 of the drawings, the platform 16 isprovided with a scale 95 arcuately arranged about the axis of theindicator shaft 54 and cooperable with the pointer 67 to provide areading. The scale 95 is calibrated to indicate the force necessary tomove the block 40 relative to the carriage 15, as the carriage movesalong the track 12, 12a.

As indicated in FIGURES 1, 2, and 3 of the drawings, a slide rod 96 issupported in parallel spaced relation to the table 10 by means ofsupporting blocks 97 at opposite ends thereof. A track 99 is mountedupon the table 10 directly beneath the guide rod 96. The track 99 iseither made of two spaced bars or is slotted as indicated at 100. Atubular rider 101 encircles the guide rod 96 :and is slidably supportedthereupon by bearings 102 recessed into opposite ends of the body of therider. A roller 103 is rotatably mounted upon a pivot pin 104 threadedinto the under surface of the rider 101 and engageable in the track 99to hold the rider from rotation about the axis of the guide rod 96. Anarm 105 is pivotably supported by a horizontal pivot pin 106 to theinner side of the rider 101, the arm 105 supporting a roller shaft 107with its axis parallel the axis of the pivot pin 106. A heavy roller 109is rotatably mounted upon the shaft 107 and i secured in position by aretaining nut 110 or other suitable means.

A base sheet supporting clamp 111 is supported by the table 10 near oneend of the table between the guide rod 96 and the track member 12. Theclamp 111 is supported by a pair of bearing blocks 112 extendingupwardly from the surface of the table to support a shaft 113 extendingtransversely of the table 10. The shaft 113 supports a pair of parallelspaced clamping arms 114 which are shown in FIGURE 2 to have down turnedclamping jaws 115. The shaft 113 also supports an intermediate operatingarm 116 extending in a direction opposite to the clamping arms 114 andhaving a bearing plate 117 at its outer extremity by means of which theoperating arm may be operated. A spring 119 has its lower end engaged ina socket 120 in the table and engages against the under surface of theoperating arm 116 to urge the jaws 114 into clamping position.

A glue spreading device 121 is shown in FIGURES 4 and 5 of the drawings.The spreader 121 includes a generally rectangular block 122 which isnotched along its under surface as indicated at 123 at opposite ends ofthe block to accommodate supporting legs 124. The under surface of theblock 122 is milled or ground away to provide a downwardly andrearwardly inclined under surface portion 125 and an upwardly andrearwardly inclined portion 126, the inclined portions 125 and 126adjoining at a round apex 127 which is spaced from the plane of theunder surface of the blocks 124 a distance equal to the thickness of thefilm of glue to be applied. Obviously, the spacing may be measured inthe thousands of an inch.

FIGURE 12 of the drawing indicates a wiring diagram which is used forcontrolling the apparatus. As indicated, a current is supplied by linewires L-1 and L-2. A main control switch 129 and fuse 130 are providedin at least one of the power lines. An indicating light 131 is providedin a conductor 132 connecting the line wires L-1 and L-2. The circuitincludes a series of relays, the first of which is identified by theinsignia CR-l. Relay CR-l includes a relay coil 133, one terminal ofwhich is connected to the line wires L-2 by a. conductor 134. The otherterminal of the coil 133 is connected by a conductor 135 which inludes anormally open starting switch 136 connected to line wire L-l. For thepurpose of explanation, the switch 136 is the starting switch of theapparatus and lies in the path of a portion of the arm 105 pivotallyattached to the rider 101. The switch 136 is directional so that therider 101 may pass over the switch without actuating the same uponmovement of the ride-r to the right as viewed in the drawings. However,upon movement of the rider to the left, the circuit is closed virtuallyat the instant when the overlying strip is pressed into contact with thebase sheet as will be later described.

The switch blade or armature 137 of the relay CR-l is moved intoengagement with the contact 139 when the coil 133 is energized, thecontact 139 being connected by the conductor 140 to the previouslydescribed conductor 135. The conductor 140 also leads to one terminal ofthe coil 141 of the second relay TDR, the other terminal of which isconnected by conductor 142 to the line wire L-2. Thus the closing of themomentarily closed switch 136 also closed the time delay relay TDR.Relay CR-l serves as :a holding relay for the time delay relay. Thiscircuit includes the switch blade 143 of a third relay CR2 which isconnected by a conductor 144 to line wire L-l and is normally in contactwith relay terminal 145 which is connected by a conductor 146 to theblade 137 controlled by relay (ZR-1. As soon as CRI coil 133 isenergized, the circuit is closed from line wire L-1 through conductor144, blade 143, contact 145, conductor 146, switch blade 137, contact139, and conductor 140 to the coil 141 of TDR to hold coil 141 as longas relay CR2 remains in unenergized condition.

The purpose of the time delay relay TDR is to delay the start of themotor 36 for a predetermined time period and thus to allow the adhesiveto set for a predetermined length of time. The relay is adjustable sothat the time which elapsed between the application of the sealingpressure and the start of the test may be regulated.

Energization of the time delay relay coil 141 functions after apredetermined time period to move the contact blade 147 into engagementwith a contact 149 which closes a circuit to the coil of relay CR4. Thiscircuit extends from line wire L-1 through conductor 150, switch 147,contact 149, and conductor 151 to the forward limit switch 152 which isnormally biased toward contact 153. Contact 153 is connected byconductor 154 to the coil 155 of relay CIR-4, the other terminal ofwhich is connected by conductor 156 to L-Z thereby closing the circuit.

Energization of the coil 155 draws the relay armature 157 against thecontact 159 closing a circuit from L1 through a conductor 160, blade 157and contact 159 to conductor 161 leading to the normally closed contact162 engaged by the armature 163 of relay CR3. The blade 163 is connectedthrough conductor 164 to the armature 165 of relay CR2 normally biasedtoward contact 166 connected by conductor 167 to the field coil 169 ofthe split phase motor 36, the other terminal of the coil being connectedby the conductor 170 to L-2. The motor 36 therein starts its movementmoving the carriage 15 toward the left as viewed in the drawings or in aso called forward direction. As indicated in FIGURES 1 and 3 of thedrawings, the forward limit switch 152 is in the path of movement of thecarriage 15 and at the end of the forward movement of the carriage theswitch 152 is engaged with a contact 171 and the circuit to the coil ofrelay CR4 is broken, stopping the motor 36.

The return of the carriage 15 to its normal position is initiated by themanually operable return switch 172 which momentarily connects contacts173. The operation of the switch 172 closes a circuit to energize bothCR2 and CR3. This circuit extends from L1 through conductor 150, relayarmature 147 contact 149, conductor 151, forward limit switch 152,contact 171, conductor 174, normally closed back limit switch 175,conductor 176, manually operable switch 172, conductor 177, and therelay coil 179 of (IR-3, the other terminal of which is connected toline wire L2 by conductor 180. The coil 181 of relay CR2 issimultaneously energized by the conductor 182 leading from conductor 176through the coil 181 and conductor 183 to L2. Energization of the relayCR2 moves the armature 143 into engagement with contact 184 closing acircuit in parallel with the forward limit switch 152 to maintain therelay CR2 and CR3 energized after the forward limit switch becomesdisengaged and open the circuit. This latter circuit extends from L-lthrough the conductor 144 relay armature 143, contact 184, conductor185, back limit switch 175, conductor 176, and conductor 182 to the coil181 of CR2 The armature 186 of relay CR-3 has been drawn into engagementwith contact 187, the blade 186 being connected by conductor 189 to 176.A contact 187 is con nected by conductor 190 to conductor 177 thusholding the relay CR-3 energized.

Relay CR2 functions to reverse motor 36. In the position illustrated, aphase shifting capacitor 191 is provided in a conductor 192 leading fromthe conductor 164 to the relay armature 193 normally engaged with thecontact 194 and connected by conductor 195 to the second field coil 196,the other terminal of which is connected to line wire L-2 by conductor170. When CR2 is energized, the relay armature 165 engages a contact 197which is connected by conductors 199 and 195 to the second coil 196.This cause the motor 36 to rotate in a reverse direction, moving theplatform 16 to the right as indicated in the drawings. At the same, thearmature 193 in engaged with contact 200 connected by conductor 201 tothe conductor 167 leading to coil 169 thus placing the phase shiftingcapacitor 191 in this circuit.

Energization of relay CR-3 caused the armature 163 to engage contact 202closing a circuit from L1 through conductor 203, contact 202, armatureblade 163, to energize the field coils of the motor 36. In other words,relay CR3 makes and breaks the circuit to the reverse field coil 196while relay CR4 acts through the normally closed contact 162 of CR3 tocontrol a current to the 7 field coil 169 to drive the motor in aforward direction.

The motor 36 continues to drive the carriage towards its startingposition until it engages the back limit switch 175 which breaks thecircuits to relays CR2 and CR3. It should be mentioned that theenergization of CR-2 breaks the circuit previously energizing CR1 andTDR thereby resetting these relays to that the entire system isdisconnected once the carriage 15 returns to its starting position. Thelocation of the back limit switch 175 is indicated in FIGURE 3 of thedrawings.

In the description of the wiring diagram, the manner in which thecarriage is reciprocated has been described. The motor 55 rotates firstin one direction and the other, acting through the pinion 29 to move thecarriage at a constant speed along the length of the rack 14. Thegeneral operation of the testing methods will now be described.

A backing sheet B is placed upon the table 10 with the surface to betested uppermost. It is placed in position against the bearing blocks112 while the clamp operating lever 116 is depressed, and the jaws 115are lowered to hold the end of the backing sheet firmly against thetable 10. With the parts in the position illustrated in FIGURE 1, a poolof the adhesive to be used is placed upon the backing sheet near theclamped end thereof, and the spreader 121 is placed upon the sheetoutwardly of the pool of adhesive. The spreader is moved longitudinallyof the backing sheet to a point closely adjoining the other end thereof.It is found that with experience, the operator will learn to employ justabout the proper quantity of adhesive to adhere the overlying strip C.However, it is also possible to wipe off excessive adhesive after theoverlying strip C has been applied.

The overlying strip C is next placed lightly upon the film of adhesive.The forward end of the overlying strip is curled upwardly to overlie theadjoining portion of the strip, and is inserted between the clampingjaws 86 and 87 of the clamp 89. The time required to go through thesesteps is surprisingly uniform. The test may now be started.

The operator grasps the rider 101 and moves the same to the right on theguide bar 96, the roller being moved through the extent of its movementand then returned to its starting position. As the slider moves to theleft on its return stroke, the starting switch 136 is momentarilyclosed, starting the apparatus in operation in the manner described. Themovement of the roller 109 over the strip C causes the two sheets to bepressed together with a predetermined weight. Thus the overlying stripis always pressed into a position with an identical pressure.

When the starting switch is actuated the time delay relay causes apredetermined time delay which, for the purpose of example, may be 30seconds. At the end of this time period, the motor 36 is energized, andthe carriage 15 is moved along its track 12, 12a at a predeterminedspeed. As the carriage moves, the strip C is peeled off from the backingsheet B, the adhesive coated surface of the portion of the strip Cremoved being uppermost as indicated in FIGURE 3. At the start of theaction, unless the adhesive is a quick setting adhesive, the pullrequired to disengage the strip C is relatively small but this pullcauses the block 40 to be moved to the right in the direction of thearrow relative to the carriage platform 16. In other words, the pullupon the strip C causes the spring 51 to compress, this action rotatingthe indicator shaft 54 to swing the pointer 67 in a clockwise direction.As the movement of the carriage is slow, the position of the pointer 67relative to the length of travel as indicated on the scale 220 extendingalong the edge of the backing sheet B may be readily noted. Usually, theglue bond separates due to failure of the adhesive to adhere during thefirst part of the operation. However, as the adhesive continues to set,the pull measured by the pointer 67 usually increases until the adhesivejoint fails to separate and a portion of the surface of one sheet willbe torn away from the remainder of the sheet as a tear bond isdeveloped. Usually the effectiveness of the adhesive increasesthroughout the operation. However, the most important point to bedetermined is the length of travel which takes place before the tearbond is accomplished and the pull required to effect this tear. Thepoint at which the tear bond is effected can be readily noted from anexamination of the backing sheet as the surface of this sheet willeither show the first areas in which a portion of the sheet has beentorn away or will otherwise show portions which have been torn from theoverlying sheet.

The glue bond tester provides a more uniform means of testing a gluebond then has been previously produced insofar as the applicant isaware. The only variables encountered stem from the times required tospread the glue and apply the overlying sheet to the adhesive. In actualpractice, it has been found that the time required to accomplish thiswork varies but one or two seconds with an experienced operator.Furthermore, the time required to apply the adhesive and to attach thestrip comprises an extremely small part of the total test time, as thetime delay relay usually provides a time delay which is many times theperiod of time required to position the overlying strip in place.Furthermore, up until the time the pressure roller has applied pressureto the strip, the two parts are not effectively adhered, and from thistime on, the period is entirely automatic.

In accordance with the patent statues, I have described the principlesof construction and operation of my glue bond tester, and while I haveendeavored to set forth the best embodiment thereof, I desire to have itunderstood that obvious changes may be made within the scope of thefollowing claims without departing from the spirit of the invention.

I claim:

1. A glue bond tester for use in determining the force required todetach an elongated flexible strip from a base sheet to which it isadhered at one end throughout a portion of its length, the testerincluding:

a table,

means adapted to secure said base sheet in face contact with said tablewith the attached strip extending in a predetermined direction,

a carriage supported for movement relative to said table along a pathparallel to said predetermined direction,

a means slidably supported by said carriage for movement parallel tosaid predetermined direction between two extreme positions,

resilient means urging said slidable means toward one said extremeposition,

attachment means on said slidable means parallel to said table andadapted to engage the other end of said strip and operable upon movementof said carriage, to peel said strip from said base sheet, the pull uponsaid attachment means tending to move said slidable means toward itsother extreme position acting against the force of said resilient means,

drive means for moving said carriage at a uniform rate along said path,

and means for indicating the relative movement between said carriage andsaid slidable means.

2. The structure of claim 1 and including a scale located adjoining saidbase sheet and extending parallel to said predetermined direction.

3. The structure of claim 1 and in which said indicating means includesa rack on said slidable member parallel to predetermined direction,

a pinion supported by said carriage and engaging said rack, and

pointer means actuated by said pinion.

4. The structure of claim 1 and in which said indicating means includesa rack on said slidable member extending parallel to the direction ofmovement thereof,

a shaft pivotally supported by said carriage and sup porting a pinionengaged with said rack,

a drive member rotatable with said shaft, and

a pointer independently rotatably mounted coaxial with said shaft androtated by said drive member.

5. The structure of claim 1 and including a roller,

means supporting said roller on said table for movement along saidpredetermined direction and engageable with said strip to press thestrip against said backing sheet with a predetermined pressure.

6. A glue bond tester for use in determining the force required todetach an elongated flexible strip from a flexible paperboard base sheetto which it is adhered along a portion of its length, the testerincluding:

a table having a generally fiat upper surface portion,

a means adapted to secure the flexible paperboard base sheet in facecontact with said table portion with said base sheet extending in apredetermined direction,

a roller supported on said table for movement back and forth over saidbase sheet in both directions, said roller being operable to press thestrip against the base sheet with a predetermined force When the stripis positioned in the path of movement of said roller,

a carriage mounted on said table for movement parallel to saidpredetermined direction,

means carried by said carriage engageable with an end of said strip andoperable, upon movement of said carriage, to peel the strip from saidbase sheet, means actuated by the pulling force upon said last namedmeans to indicate the pull exerted thereupon, electrically operateddrive means for moving said carriage along said table,

a normally open power circuit to said drive means,

and

control means actuated by movement of said roller out of contact withsaid strip to close said power circuit and to initiate movement of saiddrive means.

7. The structure of claim 6 and in which said control means is actuatedby movement of said roller in but one of said directions.

8. A glue bond tester for use in determining the force required todetach an elongated flexible strip from a base sheet to which it isadhered along a portion of its length, the tester including:

a table having a generally fiat upper surface portion,

a means adapted to secure a base sheet in face contact with said tableportion,

a roller supported on said table for movement over said base sheet in apredetermined direction, said roller being operable to press the stripagainst the base sheet with a predetermined force when the strip ispositioned in the path of movement of said roller,

a carriage mounted on said table for movement parallel to saidpredetermined direction,

7 means carried by said carriage engageable with an end of said stripand operable, upon movement of said carriage, to peel the strip fromsaid base sheet,

means actuated by the pulling force upon said last named means toindicate the pull exerted thereupon,

drive means for moving said carriage along said table,

control means actuated by movement of said roller over said strip toinitiate movement of said drive means, and

means connected to said control means for providing a time delay betweenthe time of actuation of said control means and the initiation of saidmovement of said carriage.

References Cited UNITED STATES PATENTS 816,032 3/1906 Oertel 73-1432,752,780 7/1956 Gershberg 73-150 3,129,586 4/1964 Allen et al. 73-150 XRICHARD C. QUEISSER, Primary Examiner.

J. W. MYRACLE, Assistant Examiner.

1. A GLUE BOND TESTER FOR USE IN DETERMINING THE FORCE REQUIRED TODETACH AN ELONGATED FLEXIBLE FROM A BASE SHEET TO WHICH IT IS ADHERED ATONE END THROUGHOUT A PORTION OF ITS LENGTH, THE TESTER INCLUDING: ATABLE, MEANS ADAPTED TO SECURE SAID BASE SHEET IN FACE CONTACT WITH SAIDTABLE WITH THE ATTACHED STRIP EXTENDING IN A PREDETERMINED DIRECTION, ACARRIAGE SUPPORTED FOR MOVEMENT RELATIVE TO SAID TABLE ALONG A PATHPARALLEL TO SAID PREDETERMINED DIRECTION, A MEANS SLIDABLY SUPPORTED BYSAID CARRIAGE FOR MOVEMENT PARALLEL TO SAID PREDETERMINED DIRECTIONBETWEEN TWO EXTREME POSITIONS, RESILIENT MEANS URGING SAID SLIDABLEMEANS TOWARD ONE SAID EXTREME POSITION, ATTACHMENT MEANS ON SAIDSLIDABLE MEANS PARALLEL TO SAID TABLE AND ADAPTED TO ENGAGE THE OTHEREND OF SAID STRIP AND OPERABLE UPON MOVEMENT OF SAID CARRIAGE, TO PEELSAID STRIP FROM SAID BASE SHEET, THE PULL UPON SAID ATTACHMENT MEANSTENDING TO MOVE SAID SLIDABLE MEANS TOWARD ITS OTHER EXTREME POSITIONACTING AGAINST THE FORCE OF SAID RESILIENT MEANS, DRIVE MEANS FOR MOVINGSAID CARRIAGE AT A UNIFORM RATE ALONG SAID PATH, AND MEANS FORINDICATING THE RELATIVE MOVEMENT BETWEEN SAID CARRIAGE AND SAID SLIDABLEMEANS.